Thermal Considerations - EKF SC2-PRESTO CompactPCI User Manual

® TM
User Guide • SC2-PRESTO • CompactPCI Serial CPU Board • Intel® Core 4xxx Processor

Thermal Considerations

In order to avoid malfunctioning of the SC2-PRESTO, take care of appropriate cooling of the processor
and system, e.g. by a cooling fan suitable to the maximum power consumption of the CPU chip
actually in use. The processor contains digital thermal sensors (DTS) that are readable via special CPU
registers. DTS allows to get the temperatures of each CPU core separately.
Two further temperature sensors, located in the system hardware monitor LM87, allows for
acquisition of the boards surface temperature and the thermal state of the onboard system memory
channel. Beside this the LM87 also monitors most of the supply voltages. A suitable software on
Microsoft Windows® systems to display both, the temperatures as well as the supply voltages, is
Speedfan, which can be downloaded from the web. After installation, both temperatures and
voltages can be observed permanently from the Windows® taskbar.
The SC2-PRESTO is equipped with a passive heatsink. Its height takes into account the 4HP limitation
®
in mounting space of a CompactPCI board. In addition, a forced vertical airflow through the system
3
enclosure (e.g. bottom mount fan unit) is strongly recommended (>20m /h or 2m/s (400LFM) around
the CPU slot). Be sure to thoroughly discuss your actual cooling needs with EKF. Generally, the faster
the CPU speed the higher its power consumption. For higher ambient temperatures, consider
increasing the forced airflow to 3m/s (600LFM) or more.
The table showing the supported processors above give also the maximum power consumption (TDP)
of a particular processor. Fortunately, the power consumption is by far lower when executing typical
Windows® or Linux tasks. The heat dissipation increases when e.g. rendering software like the
Acrobat Distiller is executed.
TM
The Core processors support Intel's Enhanced SpeedStep® technology. This enables dynamic
switching between multiple core voltages and frequencies depending on core temperature and
currently required performance. The processors are able to reduce their core speed and core voltage
in multiple steps down to 800MHz. Additional a reduction of the graphics core clock (down to
200MHz) and voltage is possible. This leads to an obvious reduction of power consumption resulting
in less heating.
A further way to reduce power consumption is achieved by integrating the voltage regulators on the
th TM
die of the 4 generation Core processors. This embedding allows the processor to regulate the
voltages to each core, graphics, cache and other units separately depending on their performance
needs. Parts that are currently idle may switched off to save power.
© EKF -20- ekf.com